Gas-lift pump



Jan. 3, 1939. J. P. STEPHENS ET AL GAS -LIFT PUMP 2 sheets-sieetl Filed July 25, 1935 'JAMES P sTEFr-IENSTy CLARENCE M. RADER FRANC|5 STEELE INVENTOR WILLIAM E FLOOD ATTORNEYS.

Jan. 3, 1939. J. P. STEPHENS ET AL GAS -LIFT PUMP Filed July 25, 1955 l 2 sheets-sheet 2 v INVENTOR.

JAME CLARE FRANCIS WILLIAM ATTORNEYS.

Patented Jim. s, 1939 UNITED, STATES PATENT OFFICE 2.14am v aas-nm Pour application my za. 1935. serial No. 32.193

' 11cm-ns. (c1. 10s-231) water, from well and drill holes.

The object of this invention is to provide an improved apparatus and method for raising liquids from wells, which contains a minimum of moving parts, and is positive and reliable in operation.

Other objects of this invention are to provide an apparatus and method for raising liquids from well and drill holes with a'minimum amount of gas pressure and loss of volume thereof, and with a lower gas-liquid ratio than heretofore practical, and without the necessity of intermittently releasing or bleeding all of the gas under pressure used in raising the liquid to the surface.

A further object of this invention is to provide a method and apparatus for raising liquids from wells and drill holes in such a manner that the liquid being raised is prevented fromiiowing back` Y into .the well.

A further object of this invention is to provide a method and apparatus for raising liquids from wells and drill holeswhereby the liquid being raised is kept in constant motion.

An additional object of this invention is to provide a method and apparatus for raising liquids from well and drill holes wherebyA the liquid is prevented from running back into the well hole and whereby y,it is notnecessary to overcome the inertia of the liquid each time it is raised toward v the surface.

A further additional object of this invention is to provide a method and apparatus for raising liquids from well and drill holes by the use of a gas under pressure in such a manner that no pressure is applied to and held on the strata producing the liquids.

Still further objects and advantages of this invention will be appreciated and become more apparent upon a consideration of the following specification and the -attached drawings, forming 'a part thereof, and wherein like reference characters designate like parts throughout the several views, and wherein, l

Fig. l is a fragmentary view partially in vertical cross-'sectionand partially in side view illustrating the pump for raising liquids, together with its associated parts, positioned in a well or drill hole, 1

Fig. 2 is a vertical cross-sectional view of the pump proper illustrating one-'half 0I the mechanism thereof.

` of the pump taken on line 3 3 lof Fig. 2,

Fig. 3 is another vertical cross-sectional view of the pump proper, taken at an angle lof 90 clockwise to that shown in Fig. 2,

Fig. 4 is a full horizontal cross-sectional view of the pump illustrated in Figs. 1, 2 and 3, and 5 taken on line I I of Fig. 2,

Fig. 5 is a full horizontal cross-sectional view of the pump taken on line 2 2 ofFig. 2,

Fig. 6 is a full horizontal cross-sectional view Fig. 7 is a full horizontal cross-sectional view of the pump taken on line 4 4 of Fig. 2,

Fig. 8 is a full horizontal cross-sectional view of the pump taken on line 5 5 of Fig. 2,

Fig. 9 is a full horizontal cross-sectional view 15v of the pump taken on line 6 6 of Fig. 2,

Fig. 10 is a vertical cross-sectional view of a portion of the pump taken on line 1 1 of Fig. 9 and looking in the direction 'of the arrows, and

,Fig. 11 is an enlarged illustration in vertical 2o cross-section of a pipe fitting shown in Fig. l.

Although this invention is equally adapted for raising various liquids from diiIerent types of well and drill holes, one embodiment thereof will now be described in connection with recover- 25 ing and raising liquids, such as oil and/or water.

In order to describe one embodiment of this invention there is illustrated in Fig. 1 the conven- IS is shown in Fig. 11` and includes the internally 40 screw threaded collars I8 and I8 into which ilts the casing I2. The seat I1 is formed with an annular groove 20 opening into which are a plu-I rality of ports 2I communicating with the well hole I0. Above and below the groove 2l is a 45 channel 22 each fitted with a soft metal packer ring 23. The iitting I6 serves as a support and seat for the bottom portion of the pump body Il and its function will be hereinafter more described.

A chamber 30 is formed within the lower part of the casing I2 and -is defined by the nipple -II and a plate 3| having 'an aperture 32 formed therein. Astring of tubing is secured to the lower end of the pump body 60, as shown in Figs.

1 and 3, and extends down into the chamber i 30 to a point adjacent the lower end thereof. In

the upper end of pipe 33 there is a screw threaded collar or stop 34 into which there is screwed and seated a valve seat 35 and a cage 36 containing the ball valve 31. Below the valve seat 35 the pipe 33 is formed with a plurality of slots or apertures 38 connecting the interior of the pipe with chamber 30. A disc 39 is secured in, pipe 33 just below the apertures 38 and is provided with a central aperture 40 through which passes the rod 4| having on its upper end a nut 42 to limit its downward movement to the disc 39. 'Ihe lower end of the rod 4I is secured to a cylindrical member- 43 which ts loosely within pipe 33 and is fastened to the cage 44 formed integral with the valve seat 45 adapted to t into the aperture 32 .of plate 3|. A suitable form of packing ring 46 is positioned on the plate 3| to form a tight seal therewith and the Valve seat body. A ball valve 41 is contained within the cage 44 and rests upon the valve seat 45 to seal the opening 32. 'Ihe compression spring 49, contained within pipe 33, bears against the under side of disc 39 and the upper side of the cylindrical member 43, and thereby maintains the cage 44 and seal 46 in the position shown in Fig. 1.

1t will be appreciated that the structure above described will permit the liquid, such as oil and/or water, contained in the stratum I3 to accumulate in the bottom of the well hole and when the level thereof and the pressurethereon has become sufilcient it will flow into the bull plug I4 through the apertures I5 and unseat The pump constituting this invention is of the type that is lowered into the well hole within the casing pipe by means of a string of tubing and is supported above the bull plug and a chamber, wherein the liquid accumulates, by a suitable seat. By means of a string of tubing 59 the pump body, represented generally bythe numeral 69, isl lowered into the well hole within the casing pipe or pipes and comes to rest as vshown in Fig; 1 with the lower end ofthe pump body Blisupported bythe seat I1 ofthe pipe amm; is. l

While the apparatus comprising this invention is described as a pump it is to be understood that it is of the fluid pressure lift type for raising liquids and does not include any reciprocating plungers, or clap-valves, o r the like which are normally.v present in `-pumps, but instead utilizes a minor number of parts and only a few moving members in the form of valves. It is believed that a more comprehensive understanding of this invention may be had by first describing generally its method of operation in conn'ection with one embodiment Aof the structure which may be used therewith. K In brief, a gas under pressure, such as air, is forced'down into the well hole on the inside of a jstringof casing pipe so that it will enter a minor port inthe pump body to operate a pilot valve, which serves as a controlV for a main valve. The gas under pressure here referred to, is intermittently introduced into the casing pipe and is otherwise controlled at the surface by suitable conventional mechanisms. Upon the opening of the pilot valve the gas under pressure can then enter a set-of main ports leading into a cylinder within the pump wherein there is contained a main valve in the form of a piston which is designed to control a plurality of ports. One of these ports will, with the valves at a certain position, permit the gas under pressure to enter into a passageway leading to the bottom of the well hole to force the liquid therein up through the pump and to the surface. Another of these ports will, with the valves at a different position permit the gas under pressure, which has been forced into the bottom of the well hole, to bleed oil.' or exhaust so that additional liquid may accumulate below the pump to be raised. Still another of these ports is at times at least partially opened so that gas under pressure is applied to the liquid being raised to give it a considerable lift and to prevent it from draining under pressure is not applied at all times to the' liquid in the well hole to be raised, but isV intermittently applied and exhausted so that there are intervals when the liquid can accumulate in the bottom of the well hole as it is forced thereinto by the Vbottom hole pressure. Moreover by virtue of the structure of the pump which will be directly described it is not necessary to bleed or exhaust the entire column of gas under pressure in the tubing eachtime it is necessary to bleed or exhaust the gas under pressure in the bottom of the well hole for the purpose of allowing the liquid to re-accumulate therein. Additionally. the gas under pressure used to raise the liquid does not enter the well hole and therefore is precluded from exerting any pressure on the strata producing the liquid. 'I'his last condition is most important for the reason that if the gas under pressure were applied tothe liquid bearing strata the production therefrom would be greatly decreased. l j

With' reference now to the structure of the pump, it will be noted from a consideration of Figs. 1 and 2 that the upper end thereof has connection with a string of tubing 59, the interior of which communicates with abore, passage or conduit I` formed internally of 'the body 30 and includes an upper portion 3|.', a. central portion 8l, and a lower offset port 6I"` `which communicates with the interior of pipe 33. The bore, passage or conduit II and itscomponents are of varying diameters and are positioned in the pump body 66 as is shown in Figs. ,4, 5, 6, '1, 8 and 9. Bore 3l is an eduction conduit and "it is therethrough that liquid passesonits way from the bottom of the well, the bull plug. and the chamber 3l to the surface as Yit is forced upwardly by gas under pressure.

'I'he bore, passage or conduit 63 shown in Fig. 3 is offset at the lower end thereof as shown at 82' and is an induction conduit into which through port 63, formed in the upper part thereof, gas under pressure is introducedto be directed tothe chamber 33 to raise the liquid therefrom through pipe 33, bore 8|, and pipe 58 to the surface. The relative position of the induction conduit 62 within the valve body 60 is shown in Figs. 5, 6, 'l and 8. The lower end of the induction conduit 62' is offset as shown in Fig. 3 and has at the lowermost end thereof a port 64 which connects with an annular space 65 formed between the pipe 33 and the lower end of the pump body 60. This space 65 is in directcommunication with the chamber v30 wherein the liquid accumulates as it is forced from the stratum I3 by the bottom hole pressure.

In Fig. 3 there is shown within the pump body 60, a bore 66, which is an exhaust conduit and includes a reduced top portion 66', a central portion 66, and a lower offset portion 66". The portion 66" of the exhaust conduit terminates in a port 61 which leads into a space 68 communicating with an annular chamber 69 formed in communication with the annular outlet 10. In the upper end of the central portion 66 of the exhaust conduit there is a port 1|, while in the reduced portion 66' of the exhaust conduit there are the ports 12 and 13 which will be described later. It will be noted from a consideration of Fig. 1 that the lower part of the pump body 60 includes a frustoconical end having the tapered portion 14, which when the pump is supported by the fitting |6, makes a sealed tting with the packing rings 23 and 23 set in the seat I1, thereby bringing the annular exhaust port 10 of the pump in alignment with the groove 20 formed in fitting I6 and in communication with the ports 2| which lead to the space 15 shown in Fig. 1, beyond the casing pipe I2. It is to be understood that the packing rings 23 may be formed on the bevelled face 14 at the lower end of the pump 80, and positioned thereon above and belowthe annular port 10. l

With reference now to Figs. 2 and 10, it will be seen that in the side wall of the pump body and at a point above the center thereof is a small port 84 which leads into a cylindrical chamber 85 which houses a pilot valve structure. the bottom of chamber 85 there is formed an outlet 86 and a valve seat 81. A piston 88 having a recessed portion 89 in the top thereof and provided with guide rings 90 is positioned inthe Y cylinder 85 and is of a substantially smaller diameter than the cylinder. The piston 88 is further formed with a valve head 9|, and is reciprocably movable in the cylinder to close the port 86. This structure constitutes a pilot valve and its function will be fully described in connection with the complete operation of the pump.

A means is provided to normally retain the valve head 9| upon the seat 81 to keep port 86 closed. 'I'his means comprises a collar 92, which is screwed into the upper end of the cylinder 85, and which includes a tubular portion 93 having a screw threaded connection at its upper end with a plug 94 which has a screw threaded central bore 95 toaccommodate the threaded bolt 96. The bolt 96 is provided with a head 91 and also has a lock nut 98 which is set to contact the upper face of plug 94. A cap 99 has a screw threaded connection with the upper part of plug 94 to form a housing for the bolt 96. Positioned below the plug 94 and within the upper end of cylinder 93, there is a follower |00 having a ange |0|, and a recess |02 in its upper face into" which seats the lower end of the bolt 96.

A similar follower |03, positioned in the lowerY end of cylinder 93, is -formed with a flange |04 and a recessed portion |05'into which seats the upper end of a pin |06. The pin |06 has rounded ends and the lower end and portion thereof is contained in the recess 89 formed in the cylinder 88. A coil compression spring |01 ishousedwithin the cylinder 93 and the ends thereof are forceably seated against the flanges |0| and |04 of the followers |00 and |03 respectively. As the plug 94 and follower |00 are normally stationary the spring |01 acts to force the follower |03 and pin |06 downwardly and so maintain the piston 88 in the position shown in Fig. 2 with the valve head 9| upon the seat 81 to keep port 86 closed.

This structure for maintaining the valve port 86 normally closed is capable of adjustment, and by removing the cap 99 and unscrewing the lock nut 98 to raise the same, and then by means of the bolt head 91 screwing the bolt 96 down into plug 94 the follower |00 will be forced further down into the cylinder 93 and in this manner the spring |01 will be further compressed and will exert a greater force on the disc |03, the pin |06 and the piston 88, thereby more positively retaining the valve head 9| on the seat 81.

It will lbe appreciated from a study of Fig. 1 that as air, or other gas, under pressure is forced down into the well hole in the space ||0, shown in Fig, 1, between the casing pipe l2 and the `pump body 60, that a portion thereof will enter the port 84 of the pump body. When gas under suflicient pressure enters port 84 it will continue therethrough into the lower end of the cylindrical chamber 85 and by virtue of the force that it exerts on the bottomof the piston 88 the same will be raised together with the valve head 9|, thereby opening the port 86 through which the gas under pressure will flow.

The upper end of the cylindrical chamber 85 abovev the piston 88 is in communication with the upper end of the reduced portion 66' of the exhaust conduit. With reference to Fig. 4 which is taken on line 'of Fig. 2, it will be seen that the upper portion of cylindrical chamber 85 is provided with a port ||3 which is in communi cation with port 13 in the exhaust conduit 66' by virtue of the short connecting channel H4. With this arrangement any gas or air under pressure which might leak upwardly in the cylindrical chamber 85 and past the piston 88 to a point thereabove, and which would materially hinder the desired movement of the piston as actuated by the gas under pressure entering port 84, will escape from cylinder 85 to a portion 66 of the exhaust conduit.

With reference now to Fig. 2 it will be noticed that there is formed within the pump body 63 a relatively long cylinder chamber |20 which has a frusta-conical upper end surface |2I, shown more clearly in Fig. 10, and which has opening thereinto the port 86. Within the cylinder chamber |20 there is apiston structure which Formed in the collar are a plurality of relatively small ports I 26. The lower piston head |23 has a reduced portion |21 which terminates in a head |23 constituting a seat for the upper end of a compression spring |29. The lower end of the spring |29 rests upon a seat |30 formed adjacent the bottom of the cylinder chamber |20. Into a reduced portion I3I formed at the lowermost end of the chamber |20 there is tted, as by screw threads, a hollow .tubular stop. member |32 having formed in the side walls thereof the aperture |33. The stop I3 2 will serve .to limit the downward movement of the piston heads |22 and |23 as the disc |20 attached to the latter will abut the top of the stop member.

With reference to Figs. 9 and 10, the former of which is a cross section of a portion of the pump taken on line 6-6 of Fig. 2, there is shown the cylinder chamber |20 and in a side wall thereof adjacent and in alignment with the ports |26 formed in the collar |25 Vthere is a small port |34 which by virtue of the channel |35 is connected to the port 12 in the upper portion 66' of the exhaust conduit.

Formed in an upper side wall portion of the cylinder chamber |20 and adapted to.be normally open when the piston |22 is in the position shown in Fig. 2 there is a port |36 which is more clearly shown in Fig. 5. As shown, a short channel |31 connects port |36 of chamber |20 with port 1I of the exhaust conduit 66.

Within the upper portion of the cylinder chamber |20 and below the port |36 is another port |30, which is shown in Figs. 2 and 6, and which will be open at all times regardless of the position of the piston. As shown in Fig. 6 a relatively short channel |33 connects port |33 with port 63 of the gas induction conduit 62.

Approximately intermediate of the cylinder chamber |26 there are opening thereinto the ports through which gas under pressure as supplied from the surface may enter the cylinder chamber 20 and which are clearly shown in Fig. 7, and are reprented in Fig. 2 by the dotted lines. The ports |40 are connected by relatively short channels I4I with the ports |42 which are formed in the outer surface of the pump body 60, thereby establishing communication with the chamber |20 below the piston |23, and the space |I0 between the pump body 60 and the casing pipe I2. The ports |40 are sosituated with respect to the chamber |20 that when the piston heads |22 and I 23 are in the position shown in Fig. 2, the piston head |23 will cover the upper half of these ports.

A relatively small channel |43, shown in Fig. 2, connects the cylinder chamber |20 with the liquid eduction conduit 6|. The conduit I 43 is also shown in Fig. 7 by the dotted lines. When the piston heads |22 and |23 are in the position shown in Fig. 2 the channel |43 will be in communication with the ports I4| through the cylinder chamber -I20 so that gas under pressure iiowing into the chamber |20 through the conduits |4I will escape into conduit 6| through conduit |43. It is this gas that passes through conduit |43 into the liquid eduction conduit 6I that keeps the liquid being raised therethrough, as will later be described, in constant upward movement to prevent it from draining backwardly.

Leading from the cylinder chamber |20 there is still one other channel which leads into the lower end of the central section of the exhaust conduit 66. As shown in Fig. 2 there isformed at the lower end of the chamber I 20, and in the reduced portion I3I thereof, a port |44 which communicates through channel with the port I 46 opening into the exhaust conduit 66, as shown in Fig. 8. The complete function of the above described ports will be hereinafter fully explained.

Before explaining the complete operation of the above described pump it is desired to discuss the operation of the pistons |22 and I 23, which are joined by the reduced member |24 and are movable in unison within the cylinder chamber |20. As previously pointed out the ports |36, |38, and |40 are formed in the side walls of the chamber |20 and are arranged from top to bottom in the order mentioned. Port |36 connects with the exhaust conduit 66 through channel |31 and port 1|, as shown in Fig. 5; port |33 connects with the gas induction conduit 62 through channel |35 and port 63, as shown in Fig. 6; and, ports |40 connect with the space IIO between the casing pipe I2 and the pump body through the ports |42 and channels |4I, as shown in Fig'. 7. With the piston heads I 22 and |23 held in the position shown inl Fig. 2 by the action of spring |29, the exhaust port |36 is open and in communication with the exhaust conduit 66, and the port |33 is open and in communication with the channel 62, and the ports |40 are half closed by the piston |23. This is the normal or neutral position oi' the pump.

Assuming that the various casing pipes and I2 have been set into place within the well hole and that interposed in the lower portion of the latter casing pipe is the fitting I6, now by means of a string of tubing such as the one 59, the pump body 60 having secured to the lower end thereof the pipe 33, and including the valves 31 and 41 together with their associated parts, is lowered into the well hole until the bevelled faces 14 formed on the lower end of the pump body 60 come to rest on the seat I1 of the nipple I6.

When the pump body 60 is properly in place upon seat I6 the packing rings 23 thereof will form a tight seal with the bevelled face I1, and the annular port 10 formed therein will be between the sealing rings 23 and opposite the annular groove 20 formed in the tting I6 so that the plurality of ports 2| formed therein will be in alignment and in communication with the annular port 10.

With the pump body 60 in the position described the pipe 33 will extend down into the chamber 30 formed in lower end of the casing pipe I2 and the lower end of the Valve seat 45 will ilt into the aperture 32 formed in the plate 3| and be held securely therein against the packing ring 46 by the spring 49. When the pump and its associated members are 4initially positioned in the well hole as above described the valves 31 and 41 are upon their seats 35 and 45.

Liquids. such as oil and/or water contained in the producing stratum I3, and in other similar strata adjacent thereto, will ow out into the bottom of the well hole or be forced thereinto by virtue of the bottom hole or rock pressure on the liquid. This liquid will accumulate in the well hole around the lower end of the casing pipe I2 and the bull plug I4 and will enter the latter through the apertures I5. When the liquid so accumulated has reached a considerable level or attained a suilicient pressure it will force the ball valve 41 from its seat 45 and iiow through the opening 32 formed in plate 3| into the interior of the lower end of the casing pipe I2 constituting the chamber 30. This chamber is oi.' considerable amasser length and will accommodate a great amount of liquid, and moreover its size can be readily changed and controlled to meet varying amounts of liquid encountered in the different wells. The valve 31 may be located at any convenient point within the pipe 33, and in the present assembly is positioned within the chamber 38, and while the same is filling up with liquid entering through the aperture 32 this valve 31 will be upon'its seat 35. It is to be appreciated that the chamber 30 will become substantially lled with liquid in a relatively short time and with the liquid to be raised to the surface now accumulated therein and the various parts of the pump in the position shown in Fig. 2, and the pump body located in the well hole as described and as shown in Fig. 1, a gas under pressure, such as air, is forced from the surface down the casing pipe in the space ||0 formed between the casing pipe |2 and the string of tubing 58, or the pump body 60. The gas under pressure is controlled from the surface and intermittently introduced into the space I |0, and when it reaches the pump body a small portion will enter the port 84 and flow into the lower portion of cylinder chamber 85 where it will exert a force on the under side of the piston 88 and raise the same against the action of spring |01, thus unseating the pilot valve head 8| from its seat 81 and opening the pilot port 86 which leads into the top of chamber 20. The gas under pressure will now flow into the top of cylinder chamber |20 and exert a force on the top of piston head |22 sufficient to overcome the action of spring |29, and force pistons |22 and |23 downwardly in their cylinder |20 until the head |28 meets the top of the stop |32 and thereby limits the further downward movement of the pistons. With the head |28 resting upon the top of stop '|32 the upper edge of piston |23 will be below the lower edge of the ports |40 leading into the cylinder chamber |20 between the pistons |22 and |23. This gas under pressure in the cylinder chamber |20 will escape through port |38 into channel |39 and through port 63 into the upper end of the gas induction conduit 62. The gas will continue to flow and be forced down through the conduit 62 and the lower portion 62' thereof and will pass out through port 64 into the annular' space from whence it escapes into the chamber 30.

The flow of gas under pressure as above described into chamber 30 will be-suicient to cause the ball valve 41 to seat upon the valve seat 45 and thereby close the opening 32 against the entrance of additional liquid. At the same time the gas pressure will be suilicient to force the,

liquid in the chamber 30 up into the lower end hole. During this bleeding operation it will be of pipe 33 through the openings 38 formed therein, and cause the liquid to unseat the ball valve 31 so that it will flow and be forced by the gas under pressure up into the top portion of pipe 33 and from there into the liquid eduction conduits 6|", 6|, and 6|' formed in the pump body 60. From the portion 6|' of the liquid eduction tube the liquid flows or is forced into the string of tubing 59 which delivers it to the surface.

After the gas under pressure has been supplied and is allowed to flow through the pump in the manner described for a relatively short period of time all the liquid in the chamber 30 will have been forced up through the conduits. As the gas under pressure is supplied from the surface at intervals it will at this time be cut oi! or materially reduced. When this is done the gas pressure will no longer be sumcient to maintain the piston 88 inaraisedposition andthe samewill be forced downwardly by the spring |01 thereby causing the valve head 9| to rest upon its seat 81 and so close the port 86. Dependent upon this closing of the pilot valve the spring |29 will force the pistons |22 and |23 upwardly into their normal position as shown in Fig. 2, and by doing so the piston |22 will uncover port |36 which con' |20 between the piston |23 and the .head |28 through the ports |42, channels |4| and ports |40, from whence it escapes through the relatively small passageway |43 into the liquid eduction conduit 6| formed in the valve body. This flow of gas is continuous so long as the various parts of the pump are in their respectivey positions as shown in Fig. 2, and serves as a means for continuously maintaining the liquid being raised in constant upward motion. By this function of the pump it is not necessary to overcome the inertia of the liquid in the string of tubing 59 each time liquid is raised from the chamber 3.0 as the liquid is kept in constant upward movement and cannot drain downwardly. Additionally, the gas entering the conduit 6| through the port |43 has a tendency to mix with the liquid being raised and so lighten it, and thereby make it more buoyant and easier .to lift.

With the pistons in the position as in Fig. 2, gasy under pressure will not be forced down into the chamber 30 as port |40 is disconnected from port |38 by virtue of the piston |23 being disposedtherebetween. But ports |38 and |36 are in communication as they are now disposed between pistons |22 and |23, and with such conditions existing the gas under pressure may bleed from or be exhausted from chamber 30 through space 65 up into the conduits 62' and 62 and fron thence through port 63, channel |39, port |38 and into the cylinder chamber |20 between the pistons |22 and |23. From the cylinder chamber |20 the gas bleeds-out through port |36 and channel |31, from whence it bleeds through the lower exhaust conduit 66', through port 61, space 68 and 69, and out through the annular port 10. The annular port 10, as shown in Fig. 1, is in communication with theA ports 2| formed in the fitting |6, and it is through these ports that the gas ultimately escapes into thespace 15 formed between the casing pipe |2 and the side walls of the well noted that substantially only the gas from chambei'. 30 is exhausted, and the entire volume of gas in the space I0, between the casing |2 and pump body 60 is retained, and it is not necessary to exhaust this gas in order to bleed the gas from chamber 30.

As the gas is' being exhausted from the chamber 30 the valve 31 will be retained by gravity upon its seat 35. During the exhaustion of the gas, the liquid will again ow from strata 3 or be forced outwardly therefrom by the rock or bottom hole pressure and will accumulate in the chamber 30 as previously described. At about this time the gas pressure apparatus at the surface will re-admit gas under pressure, and on the gas being forced down into the space ||0 between the rcasing |2 and the pump body 60 it will again re-enter the port 84 to lift the pilot valve 9| from its seat. Upon the opening of the pilot valve the pistons |22 and |23 will again be forced downwardly and in so doing the exhaust port |36 is closed by piston |22 and ports |38 and |40 are again brought into communication so that the gas can flow into the chamber 30 as previously taught, to raise therefrom the liquid and force it up into the string of tubing and to the surface. l

The above described operation and function of the pump constitutes a complete cycle of its operation and by controlling the gas pressure from the surface as by automatic means, and increasing and decreasing yit at set intervals the pump can be intermittently operated in a most eillcient and satisfactory manner to raise the liquid with a minimum gas input, and with a low gas-liquid ratio.

In conjunction with the above described operation of the pump there are further minor functions which make it practical and cause it to operate in a smooth and encient manner. For instance, any gas under pressure which may escape upwardly past the piston 88 would tend to act as a buier for the same and prevent it from being readily raised by the gas entering the port 84. To overcome such a condition any gas getting past the piston 88 into the upper end oi' cylinder 85 will escape through port ||3, shown in Figs. 4 and 10, into the channel ||4 and thence into the upper portion 6.6' of the main exhaust port 66. Furthermore when the valve head 9| of the piston 88'reseats upon the valve seat 81 there will be considerable gas under pressure trapped in the upper portion of the cylinder chamber |20 above the piston |22 which will tend to prevent the pistons |22 and |23 being returned rapidly to their normal positions bythespring |29. To overcome this detrimental condition any gas so trapped will escape through port |34 which is of a lesser diameter than port 84 and which is shown in Fig. 9, into the channel |35 and through port 12 into the upper end 66 of the main exhaust conduit 60. There is also provided a port |44 formed at the lower end of cylinder chamber |20. Any gas leaking past the piston |23 and disc |28 into the lower end of the chamber |20 would tend to prevent the pistons |22 and |23 from being readily forced downwardly by the gas under pressure entering the ports 84 and 86, so-as to overcome this condition any gas leaking into the chamber |20 below the piston 23 will escape through port |44, channel |45, and port |46 into the exhaust conduit 66.

What we claim and desire to secure by Letters Patent is:

1. A device for raising liquids comprising a chamber for the accumulation of the same, a conduit in communication with said chamber for the introduction thereinto oi.' an actuating. gas under pressure, a second conduit in communication with said chamber for the eduction of liquid therefrom, and gas operated valve means to control the flow of said gas through said first named conduit, and a pilot valve operated by variable pressures of said actuating gas to control the admission of gas to said iirst valve.

2. In a device for raising liquids from wells, a tubing string extending within said well, a check valve adjacent one end of the tubing string, a seat on the tubing string provided with a passage in communication with the exterior of said string, a second tubing string extending within said rst named string and forming an annular space therebetween, a pumping element on said second string having a portion cooperating with said seat to form a liquid accumulation chamber at the lower end of the rst named tubing string, a gas induction conduit in said element in communication with said chamber and the annular space for the induction of gas pressure to said chamber, a liquid eduction conduit in said element in communication with said chamber and said second tubing string, a check valve in said last named conduit, a gas exhaust conduit in said element in communication with said gas induction conduit and said seat passage, and valve means in said element for controlling the admission of gas to said chamber and the exhaust of gas therefrom.

3. In a device for raising liquids from a Well, a tubing string extending within the well and provided with a check valve adjacent one end thereof, a source of gas under pressure in communication with said tubing string, a seat on said tubing string, asecond tubing string within said first named string, a pumping element on said second string provided with a portion cooperating with said seat to form a liquid accumulation chamber in said rst named tubing string, a conduit in said element for the conduction of gas pressure from said rst named tubing string to said chamber, a conduit in said element for the conduction of liquid from said chamber to said second tubing string, and means in said element to control the flow of gas through said gas conduction conduit.

4. A pumping apparatus for raising liquids from Wells comprising in combination, a tubing string extending Within the well to a point below the iiuid level therein and provided with a check valve adjacent one end thereof, a source of gas under pressure in communication with said tub-` ing string, a seat on said tubing string, a second tubing string within said first named string, a pumping element on said second string adapted to cooperate with said seat to form a liquid accumulation chamber in said rst named tubing string, a conduit in said element for the conduction of liquid from said chamber to said second tubing string, and means in said element respQnsive to changes in gas pressure in said rst named tubing string to control the admission of gas to said chamber through said gas conduit.

5. In a pumping element for a pumping apparatus including a body having gas and liquid passages therein, a valve chamber in said body. a main valve slidable in said chamber to control the ilow of gas through said gas passages, a gas pressure operated pilot valve controlling the admission of gas under pressure to one side of said main valve to operate the latter.

6. In a pumping element for use in well pumping apparatus utilizing gas under pressure as the actuating medium, a body having gas and liquid passages therein, a valve chamber in communication with said gas passages, a gas-pressure actuated main valve for controlling the flow of gas through said passages, and means responsive to Variations in gas pressure to control the admission of gas to actuate the main valve.

7. In a pumping element for use in well pumping apparatus in which gas under pressure constitutes the pumping medium, a body having gas and liquid passages therein, a main valve in said body actuated by gas pressure for controlling the flow of gas through said passage, and means adjacent said main valve responsive to changes in gas pressure to control the admission of actuating gas to said main valve.

8. In a pumping apparatus to be operated by gas under pressure, a pumping element comprising a body member provided with gas induction, liquid eduction, and gas exhaust passages therein, a main valve chamber in communication with said gas induction and gas exhaust passages and provided with gas admission ports in communication with the exterior thereof, a valve slidable within said chamber constructed and arranged alternately to place said gas admission port in communication with said gas induction passage, and said induction passage in communication with said exhaust passage, and a pilot valve operated by variable pressures of said actuating gas to. control the admission of gas to said iirst valve.

9. A device for raising liquids comprising a chamber for the accumulation of the same, a conduit in communication with said chamber for the introduction thereinto of an actuating gas under pressure, a second conduit in communication with said chamber for the eduction of liquid therefrom, a gas operated valve means to control the iiow of said gas through said iirst named conduit and means operated by variable pressures of said actuating gas to control the admission of gas to said valve means.

10. In a pumping apparatus to be operated by gas under pressure, a pumping element comprising a body member provided with gas induction, liquid eduction and gas exhaust passages therein,

a main valve chamber in communication with said gas induction and gas exhaust passages and provided with gas admission ports in communication with the exterior thereof, a valve slidable within said chamber constructed and arranged alternately to place said gas admission port in communication with said gas induction passage, and said induction passage in communication with said exhaust passage, and means operated by variable pressures of said actuating gas to control the admission of gas to said valve.

11. In a pumping apparatus to be operated by gas under pressure, a pumping element comprising a body member provided with gas induction, liquid eduction and gas exhaust passages therein, a main valve chamber in communication with said gas induction and gas exhaust passages and provided with gas admission ports in communication with the exterior thereof, a valve slidable within said chamber constructed and arranged alternately to place said gas admission port in communication with said gas induction passage, and said induction passage` in communication with said exhaust passage, and a pilot valve operated by variable pressure of said actuating gasto control the admission oi' gas to said valve.

JAMES P. STEPHENS. CLARENCE M. RADER. FRANCIS E. STEELE. WILLIAM F. FLOOD. 

